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Vietnam Finds Itself Vulnerable if Sea Rises

CAI RANG, Vietnam — For centuries, as monsoon rains, typhoons and wars have swept over them and disappeared into the sunshine, the farmers and fishermen of the Mekong Delta have drawn life from the water and fertile fields where the great river ends its 2,700-mile journey to the sea.

The rhythms of life continue from season to season though, like much of the country, the delta is moving quickly into the future, and industry has begun to pollute the air and water.

But everything here, both the timeless and the new, is at risk now from a threat that could bring deeper and longer-lasting disruptions than the generations of warfare that ended more than 30 years ago.

In a more modest projection, it calculates that one-fifth of the delta would be flooded, said Tran Thuc, who leads Vietnam’s National Institute for Hydrometeorology and Environmental Sciences and is the chief author of the report.

Storm surges could periodically raise that level, he said, and experts say an intrusion of salt water and industrial pollution could contaminate much of the remaining delta area.

The risks of climate change for Vietnam go far beyond the Mekong Delta, up into the Central Highlands, where rising temperatures could put the coffee crop at risk, and to the Red River Delta in the north, where large areas could be inundated near the capital, Hanoi.

Climate experts consider this nation of an estimated 87 million people to be among the half-dozen most threatened by the weather disruptions and rising sea levels linked to climate change that are predicted in the course of this century.

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An estimated 85 percent of the people in the Mekong Delta are supported by agriculture.Credit
Chau Doan for The New York Times

If it rises by 15 feet, 35 percent of the population and 16 percent of the country’s land area could be affected, the document said.

The government report emphasizes that the predictions represent the threat, based on current models, if no measures are taken in the coming decades, like building dikes.

But the potential disruptions and the tremendous cost of trying to reduce their impact could slow Vietnam’s drive to emerge from its postwar poverty and impede its ambitions to become one of the region’s economic leaders.

In addition to rising seas in the Mekong Delta, climatologists predict more frequent, severe and southerly typhoons, heavier floods and stronger storm surges that could ultimately drive hundreds of thousands of people from their homes.

Climate refugees could swell the population of Ho Chi Minh City, on low-lying land just north of the delta, as war refugees did when it was known as Saigon.

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A fishermens dock in Ben Tre. If sea levels rise by three feet, 11 percent of Vietnams population could be displaced, a World Bank paper says.Credit
Kevin German/Luceo Images

But the city itself is also at risk, says the government study, prepared by the Ministry of Natural Resources and Environment. Up to one-fourth of the city’s area would be threatened by rising floodwaters if the sea level rose by three feet.

“Ho Chi Minh City could have a double impact if sea levels rise and living conditions in the delta are not sustainable,” Mr. Thuc, the lead author of the government report, said in an interview.

His report assesses only the climatological risks, he said, and a great deal more work needs to be done to try to determine their social and economic impacts and the probable effect on population displacement.

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Because of the uncertainties of climate change and the variables of mitigation measures, it is impossible to rank nations precisely on a scale of risk, Mr. Neefjes said.

However, the 2007 World Bank working paper studied 84 coastal developing countries and found Vietnam to be the most threatened in terms of percentage of population affected, and second only to the Bahamas in terms of percentage of land area affected, if no mitigating measures are taken.

“Among all of the indicators used in this paper, Vietnam ranks among the top five most impacted countries,” the paper says. It did not include some small island nations like the Maldives and Tuvalu that are also threatened with severe inundation.

A report by the Intergovernmental Panel on Climate Change listed the Mekong Delta, Bangladesh and the Nile Delta in Egypt as the world’s three “hot spots” for potential migration because of their combination of sea-level rise and existing population.

As a region, Southeast Asia is disproportionately vulnerable, with only 3.3 percent of the world’s land mass but more than 11 percent of its coastline, the Asian Development Bank said in a report it released this year.

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But Vietnam has at least recognized the problem and begun to address it, Mr. Neefjes said. “Faster than any developing country, it has actually developed a sensible national program to start responding,” he said.

Those plans include an attempt to integrate environmental concerns into the development plans of ministries and enterprises, modifications that could conflict with their ambitions for growth, he said.

Experts said Vietnam’s primary approach — the hugely expensive construction and reinforcement of thousands of miles of dikes — would bring its own set of problems.

In the delta, they said, the barriers will probably inhibit the self-cleansing mechanism of rivers and trap millions of cubic yards of industrial waste, hundreds of thousands of tons of industrial rubbish, and millions of tons of pesticides and fertilizer that are used in fish farms and shrimp farms.

“If one-third of the delta’s area is flooded by seawater, losses would be huge,” Vo Hung Dung, director of the Chamber of Commerce and Industry’s Can Tho city branch, said last month in the newspaper Tuoi Tre. “But if the entire delta is polluted by wastewater, the losses could be many times higher.”

Here on the tiny Hau River, which winds through shaded groves of palm, bamboo and mangrove just south of Can Tho in the heart of the delta, there seems to be little awareness of these concerns.

Nguyen Thanh Chanh, 29, who fishes with his wife in a small boat, said that he sometimes listened to the radio and sometimes drank with friends at the end of the day, but that he had never heard any talk of climate change.

Life is already hard, and the rivers already flood during the monsoon season from June to November, from the swollen currents of the Mekong, from heavy rains and from tidal flooding.

An estimated 85 percent of the people in the delta are supported by agriculture.

“Those who farm go to the fields, and those who fish go to the rivers,” said Huynh Thuy, 47, a farmer. “They don’t worry much about the future.”

A version of this article appears in print on September 24, 2009, on Page A6 of the New York edition with the headline: Vietnam Finds Itself Vulnerable If Sea Rises. Order Reprints|Today's Paper|Subscribe